STUDIES ON THE EFFECT OF CORE AND SURFACE CROSS-LINKING AGENTS IN PECTIN BEADS ON THE ENTRAPMENT OF INSULIN

Ionotropic gelation, a characteristic property, has become one of the easy, simple and mild ways of encapsulating variety of drugs, enzymes and proteins, prepared by various polysaccharides. The externally cross linked beads with calcium chloride and zinc chloride were suitable for water soluble and low molecular weight drugs. Insulin, encapsulated in a calcium pectinate gel beads by dispersing the insulin and core cross linking agent in a Solution of pectin, beads are prepared by dropping the dispersion in calcium chloride by inotropic gelation. The purpose of study was to improve the entrapment efficiency of high molecular weight drugs like insulin with internally cross-linking agents like calcium carbonate. Calcium pectinate beads containing insulin was prepared by surface cross linking with 1% and 5% w/v calcium chloride solution using calcium carbonate as internal gelling agent. Beads obtained using 1% w/v calcium chloride solution showed more drug entrapment than 5% calcium chloride solution. The core and surface cross linking of pectin beads improves drug loading by about 10 – 20% compared to the surface cross linked beads. The beads were characterized by particle size analysis, swelling ratio, SEM, DSC and in-vitro drug dissolution. The current study reveals that the internal cross linking agent marginally helps to improve the entrapment efficiency of insulin in the calcium pectinate beads.